/* Copyright 2002 Jeff Dike
 * Licensed under the GPL
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <pwd.h>
#include <grp.h>
#include <net/if.h>
#include <sys/ioctl.h>
#include <linux/if_tun.h>

//MK
#include "../logutils.h"
//MK

/* TUNSETGROUP appeared in 2.6.23 */
#ifndef TUNSETGROUP
#define TUNSETGROUP   _IOW('T', 206, int)
#endif

static void Usage(char *name) {
	fprintf(stderr, "Create: %s [-b] [-u owner] [-g group] [-t device-name] "
	"[-p|-n] [-f tun-clone-device]\n", name);
	fprintf(stderr,
			"Delete: %s -d device-name [-f tun-clone-device]\n\n", name);
	fprintf(stderr,
			"The default tun clone device is /dev/net/tun - some systems"
			" use\n/dev/misc/net/tun instead\n\n");
	fprintf(stderr, "-b will result in brief output (just the device name)\n");
	fprintf(stderr, "-n will result in a point-to-point tun device,\n");
	fprintf(stderr, "-p in an ethernet tap device. Default is a tap,\n");
	fprintf(stderr, "   except the device contains \"tun\" in the name.\n");
	exit(1);
}

int main(int argc, char **argv) {
	struct ifreq ifr;
	struct passwd *pw;
	struct group *gr;
	uid_t owner = -1;
	gid_t group = -1;
	int tap_fd, opt, delete = 0, brief = 0, type = 0;
	char *tun = "", *file = "/dev/net/tun", *name = argv[0], *end;

	LOGV("tunctl start1");
	printf("tunctl start2");


	while ((opt = getopt(argc, argv, "bd:f:npt:u:g:h")) > 0) {
		switch (opt) {
		case 'b':
			brief = 1;
			break;
		case 'd':
			delete = 1;
			tun = optarg;
			break;
		case 'f':
			file = optarg;
			break;
		case 'p':
			if (type != 0)
				Usage(name);
			type = IFF_TAP;
			break;
		case 'n':
			if (type != 0)
				Usage(name);
			type = IFF_TUN;
			break;
		case 'u':
			pw = getpwnam(optarg);
			if (pw != NULL) {
				owner = pw->pw_uid;
				break;
			}
			owner = strtol(optarg, &end, 0);
			if (*end != '\0') {
				fprintf(stderr,
						"'%s' is neither a username nor a numeric uid.\n", optarg);
				Usage(name);
			}
			break;
		case 'g':
			gr = getgrnam(optarg);
			if (gr != NULL) {
				group = gr->gr_gid;
				break;
			}
			group = strtol(optarg, &end, 0);
			if (*end != '\0') {
				fprintf(stderr,
						"'%s' is neither a groupname nor a numeric group.\n", optarg);
				Usage(name);
			}
			break;

		case 't':
			tun = optarg;
			break;
		case '?':
		case 'h':
		default:
			Usage(name);
		}
	}

	argv += optind;
	argc -= optind;

	if (argc > 0)
		Usage(name);

	if ((tap_fd = open(file, O_RDWR)) < 0) {
		fprintf(stderr, "Failed to open '%s' : ", file);
		perror("");
		exit(1);
	}

	if (type == 0) {
		type = strstr(tun, "tun") ? IFF_TUN : IFF_TAP;
	}

	memset(&ifr, 0, sizeof(ifr));

	ifr.ifr_flags = type | IFF_NO_PI;
	strncpy(ifr.ifr_name, tun, sizeof(ifr.ifr_name) - 1);
	if (ioctl(tap_fd, TUNSETIFF, (void *) &ifr) < 0) {
		perror("TUNSETIFF");
		exit(1);
	}

	if (delete) {
		if (ioctl(tap_fd, TUNSETPERSIST, 0) < 0) {
			perror("disabling TUNSETPERSIST");
			exit(1);
		}
		printf("Set '%s' nonpersistent\n", ifr.ifr_name);
	} else {
		/* emulate behaviour prior to TUNSETGROUP */
		if (owner == -1 && group == -1) {
			owner = geteuid();
		}

		if (owner != -1) {
			if (ioctl(tap_fd, TUNSETOWNER, owner) < 0) {
				perror("TUNSETOWNER");
				exit(1);
			}
		}
		if (group != -1) {
			if (ioctl(tap_fd, TUNSETGROUP, group) < 0) {
				perror("TUNSETGROUP");
				exit(1);
			}
		}

		if (ioctl(tap_fd, TUNSETPERSIST, 1) < 0) {
			perror("enabling TUNSETPERSIST");
			exit(1);
		}

		if (brief)
			printf("%s\n", ifr.ifr_name);
		else {
			printf("Set '%s' persistent and owned by", ifr.ifr_name);
			if (owner != -1)
				printf(" uid %d", owner);
			if (group != -1)
				printf(" gid %d", group);
			printf("\n");
		}
	}
	return (0);
}
